Stephanie, All
Here's my suggestion for a 10 M beacon. If you homebrew currently
with modest success you can probably build it...
Mix a 24.0 mHz crystal and a 4.194 crystal with a 612 mixer...yup,
no expensive custom-cut crystals, just a couple of half-buck uP
crystals. That will get you to the bottom of the US beacon band I
believe...28.194 mHz. For the crystals oscillators use VXOs...you can
bend the crystals up into the beacon band a ways, no doubt, in that
manner. Might try using a couple of old air varicaps to tune the
crystals to maximize stability as much as possible...no tuning diodes.
After the mixer-- a double-tuned bandpass filter, then a couple of amps
to bring it up to the output level you desire. I would use a keyer chip
with a memory to run it...maybe from Jackson Harbor, they have some with
memory, perhaps enough for a beacon. Also, if you wanted to get a bit
fancy... build/install it in an insulated box with a small light bulb
for a heater to stabilize the temp even more...ah...the possibilities
are endless...
Now, I'm just a farmboy with an active imagination, not an RF
engineer...
Mike N0MF
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